In general, a communication terminal includes an antenna apparatus to transceive an electromagnetic wave. The antenna apparatus makes a resonance in a specific frequency band to transceive the electromagnetic wave having the frequency band. In this case, when the antenna apparatus makes a resonance in the frequency band, impedance has an imaginary number. Further, an S parameter of the antenna apparatus is rapidly reduced in the frequency band.
To this end, the antenna apparatus includes a conducting wire having an electrical length of λ/2 in relation to a wavelength λ corresponding to a desired resonance frequency band. The antenna apparatus transmits the electromagnetic wave through the conducting wire and the electromagnetic wave forms a standing wave in the conducting wire so that resonance is made in the antenna apparatus. In this case, the antenna apparatus may include a plurality of different conductive wires s to expand a resonance frequency band.
However, since the length of the conductive wire is determined depending on a resonance frequency band in the antenna apparatus, the size of the antenna apparatus is determined depending on the frequency band. Accordingly, as the resonance frequency band to be realized in the antenna apparatus is narrowed, the antenna apparatus may be enlarged. The enlargement of the antenna apparatus is more made as the number of conductive wires is increased. In other words, as the resonance frequency band is expanded in the antenna apparatus, the antenna apparatus may be enlarged.